What's does it means to have a soft left knee?

[doublesuited77]

been told this a few times and I really don get what it means.

[Fatphil]

I never heard it described that way but my guess is it applies to iron play.  In order to compress the ball you need to maintain your chest at impact at a the same level as address, not a particularly easy thing to do if you are not in good shape & stretched out.  However if you do keep your body in a level position but cast or early release you will hit 6" behind the ball.

Since most golfers cast, the only way to make contact is to pop up which usually means straighting your lead knee.

Since you're a 2 hdcp you are probably compressing the ball fine & your leg action is natural. For me, I'm 54 and an 8 hdcp.  The stress this move puts on my left knee is not to be joked with, so I am very careful as to how I "get back" to the ball.  My iron play suffers because of this.